The tower is hollow with about 1/4" insulation. Use a
small 15 CFM blower with enough
flex tube to route from the blower up into the tower behind the faucets. This flex tube is inside of a 3" flex or PVC tube. This larger tube needs to be air tight and very well insulated on the outside and routed between your freezer to the base of the tower. The two products lines can then be routed through the larger tube.
As to the surgery on the freezer, be careful not to cut a thermostat line. Preferably try to cut the hole (3") so that it is a straight shot to the tower.
Scott Zuhse, Instructor
Micro Matic Dispense Institute